Our quality guidelines prohibit manipulative or deceptive behavior, and this stance has remained unchanged since the guidelines were first published over a decade ago. Recently, we’ve seen some user complaints about a deceptive technique which inserts new pages into users’ browsing histories. When users click the "back" button on their browser, they land on a new page that they've never visited before. Users coming from a search results page may think that they’re going back to their search results. Instead, they’re taken to a page that looks similar, but is actually entirely advertisements:

To protect our users, we may take action on, including removal of, sites which violate our quality guidelines, including for inserting deceptive or manipulative pages into a user's browser history. As always, if you believe your site has been impacted by a manual spam action and is no longer violating our guidelines, you can let us know by requesting reconsideration.